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Flashcards in Fiser Chapter 36 COLORECTAL Deck (130)
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1

HNPCC patient gets CRC, what is tx?

Total proctocolectomy with the first cancer operation

50% get metachronous lesions within 10 years, often have multiple primaries

2

UC toxic colitis tx

NG tube, fluids, steroids, bowel rest, abx (cipro/flagyl)

50% need surgery

Avoid barium enemas, narcotics, anti-diarrheals, anti-cholinergics

3

Carcinoid of colon and rectum

Infrequent cause of carcinoid (15%)
Mets related to size of tumor
2/3 of colon carcinoids have either local or systemic spread

Tx: resect
Low rectal < 2 cm: wide local excision with negative margins
Low rectal > 2 cm or invasion of muscular propria: APR
Colon or high rectal: formal resection with adenectomy

4

Effect of radiation on CRC

When combined with chemo: decreases local recurrence and increases survival

5

Colonic obstruction causes

1. Cancer
2. Diverticulitis

6

UC tx

Sulfasalazine or 5-ASA
Loperamide (avoid in toxic colitis)

Acute: steroids, consider cyclosporine or infliximab

7

APR side effects

Impotence and bladder dysfunction from injured pudendal nerves

8

Denonvilliers fascia

Anterior rectovesicular fascia (men) or rectovaginal fascia (women)

9

Pathology shows T2 lesion after transanal excision of rectal polyp, what is tx

APR or LAR

10

CRC main gene mutations

ADK53:

APC, DCC, K-ras, p52

11

Turcot's syndrome

FAP with colon cancer and brain tumors

12

Inferior rectal artery comes off of what?

Internal budendal (off internal iliac)

13

Sigmoid volvulus risk factors

-High-fiber diets (Iran)

-Debilitated psychiatric patients, neurologic dysfunction, laxative abuse

14

Ogilvie's treatment

Correct lytes (especially K), stop drugs that slow gut, NGT
If colon >10 cm (high risk perf) -> decompress with colonoscopy and neostigmine, cecostomy if fails

15

Plicaue semilunares

Transverse bands that form haustra

16

Most common major morbidity after UC surgery with ileoanal anastomosis

Leak most common: drainage and abx
Infectious pouchitis: flagyl

17

Superior rectal artery comes off of what?

IMA

18

N staging for CRC

N: Negative nodes

N1: 1-3 nodes

N2: 4 or more nodes

N3: central nodes positive

19

Indications for surgery in diverticulitis

Total obstruction not resolved with medical therapy, perforation, or abscess formation not amenable to perc drainage, or inability to exclude cancer

-Resect all of sigmoid down to superior rectum

20

Causes of megacolon

Hirschprung's: rectosigmoid most common, dx rectal biopsy

Trypanosoma cruzi: most common acquired cause, secondary to destruction of nerves

21

Azotemia after GI bleed

Caused by production of urea from bacterial action on intraluminal blood (increases BUN, also get increased total bili)

22

Watershed areas

Griffith's (splenic flexure)
Sudeck's (upper rectum where superior and middle rectal arteries join)

23

Amoebic colitis

Entamoeba histolytica from contaminated food and water with feces that contain cysts

Primary: colon
Secondary: liver

Risk factors: Mexico, EtOH

Symptoms: similar to US dysentery; chronic more common form (3-4 BMs/ day, cramping, fever)

Dx: endoscopy -> ulceration, trophozoites, 90% anti-amebic Abs
Tx: Flagyl, diiodohydroxyquin

24

Diverticula

Herniation of mucosa through colon wall at sites where arteries enter muscular wall, circular muscle thickens adjacent to diverticulum with luminal narrowing, present in 35% population

Caused by straining

Most occur on left side in sigmoid colon (80%)
Bleeding more likely with R sided
Diverticulitis more likely with L sided

25

MCC lower GI bleed

Diverticulosis bleeding: caused by disrupted vasa rectum, creating arterial bleeding, usually significant, 75% stops spontaneously, 25% recurs

26

APR indications

Malignant sigmoid or rectal lesions (not benign), that are not amenable to LAR (need at least 2 cm margin (2 cm from levator ani muscles), otherwise need APR)

27

Neutropenic typhlitis

Tx: abx, will improve when WBC increases

Surgery ONLY for free perf (not pneumatosis intestinalis)

28

Stump pouchitis

Diversion or disuse proctitis

Tx: Short-chain fatty acids

29

When is APR or LAR indicated (rather than transanal excision)?

Low rectal T2 or higher

30

UC characteristics

Mucosa and submucosa inflammation

Unusual to have strictures or fistulae

Spares anus: starts in rectum, contiguous

Bleeding, mucosal friability, pseudopolyps and collar button ulcers

Backwash ileitis possible

Crypt abscesses